From b7319c61489acce6c8b09fe9e0af1a0c9ea68091 Mon Sep 17 00:00:00 2001
From: ridethepig <protonghost@163.com>
Date: Wed, 15 Feb 2023 13:23:26 +0000
Subject: [PATCH] lab1 ok(simple ver)

---
 libsponge/stream_reassembler.cc | 41 +++++++++++++++++++++++++++++----
 libsponge/stream_reassembler.hh |  9 +++++++-
 2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/libsponge/stream_reassembler.cc b/libsponge/stream_reassembler.cc
index 988df9f..76c9a08 100644
--- a/libsponge/stream_reassembler.cc
+++ b/libsponge/stream_reassembler.cc
@@ -1,5 +1,6 @@
 #include "stream_reassembler.hh"
 
+#include <algorithm>
 // Dummy implementation of a stream reassembler.
 
 // For Lab 1, please replace with a real implementation that passes the
@@ -8,19 +9,51 @@
 // You will need to add private members to the class declaration in `stream_reassembler.hh`
 
 template <typename... Targs>
-void DUMMY_CODE(Targs &&... /* unused */) {}
+void DUMMY_CODE(Targs &&.../* unused */) {}
 
 using namespace std;
 
-StreamReassembler::StreamReassembler(const size_t capacity) : _output(capacity), _capacity(capacity) {}
+StreamReassembler::StreamReassembler(const size_t capacity)
+    : _output(capacity), _capacity(capacity), _aux_buffer(capacity, '\0'), _aux_buffer_valid(capacity, false) {}
+// pre-allocate is working
 
 //! \details This function accepts a substring (aka a segment) of bytes,
 //! possibly out-of-order, from the logical stream, and assembles any newly
 //! contiguous substrings and writes them into the output stream in order.
 void StreamReassembler::push_substring(const string &data, const size_t index, const bool eof) {
     DUMMY_CODE(data, index, eof);
+    _unread = _unassem - _output.buffer_size();
+    _aux_buffer.resize(_capacity - _output.buffer_size(), '\0');
+    _aux_buffer_valid.resize(_aux_buffer.size(), false);
+
+    if (eof) {
+        _eof = index + data.size();
+    }
+    auto start = std::max(index, _unassem);
+    auto end = std::min(index + data.size(), _unread + _capacity);
+    for (auto i = start; i < end; ++i) {
+        _aux_buffer[i - _unassem] = data[i - index];
+        if (!_aux_buffer_valid[i - _unassem]) {
+            _aux_buffer_valid[i - _unassem] = true;
+            _unassem_count++;
+        }
+    }
+    std::string wr_data;
+    while (!_aux_buffer_valid.empty() && _aux_buffer_valid.front()) {
+        wr_data.push_back(_aux_buffer.front());
+        _aux_buffer.pop_front();
+        _aux_buffer_valid.pop_front();
+        ++_unassem;
+        --_unassem_count;
+    }
+    if (_unassem == _eof) {
+        _output.end_input();
+    }
+    if (wr_data.size()) {
+        _output.write(wr_data);
+    }
 }
 
-size_t StreamReassembler::unassembled_bytes() const { return {}; }
+size_t StreamReassembler::unassembled_bytes() const { return _unassem_count; }
 
-bool StreamReassembler::empty() const { return {}; }
+bool StreamReassembler::empty() const { return (_unassem_count == 0); }
diff --git a/libsponge/stream_reassembler.hh b/libsponge/stream_reassembler.hh
index a14c1e2..a1a3dfd 100644
--- a/libsponge/stream_reassembler.hh
+++ b/libsponge/stream_reassembler.hh
@@ -4,6 +4,7 @@
 #include "byte_stream.hh"
 
 #include <cstdint>
+#include <deque>
 #include <string>
 
 //! \brief A class that assembles a series of excerpts from a byte stream (possibly out of order,
@@ -13,7 +14,13 @@ class StreamReassembler {
     // Your code here -- add private members as necessary.
 
     ByteStream _output;  //!< The reassembled in-order byte stream
-    size_t _capacity;    //!< The maximum number of bytes
+    size_t _capacity{};  //!< The maximum number of bytes
+    size_t _unread{};    //!< The index (in the stream) of the first unread byte
+    size_t _unassem{};   //!< The index (in the stream) of the first unassembled byte
+    size_t _unassem_count{};
+    std::deque<char> _aux_buffer;        //!< auxiliary storage, initially allocated _capacity bytes
+    std::deque<bool> _aux_buffer_valid;  //!< indicate whether the bit in _aux_buffer is filled with a valid byte
+    size_t _eof{static_cast<size_t>(-1)};
 
   public:
     //! \brief Construct a `StreamReassembler` that will store up to `capacity` bytes.